Ask Slashdot: Single Sign-On To Link Google Apps and Active Directory?

trazom28 writes to seek answers to a problem faced by many businesses (and, as in this case, schools): "We are looking for a solution to a single sign on to coordinate Active Directory and Google. You can sync the passwords easily enough with Google Apps Password Sync, but ideally we would like the students and staff to be able to sign in once and be done. Additionally, the Google login requires the @domain.k12.wi.us so it would have to take the AD username, pass it along and tack on the domain to log into Google.

Has anyone seen any solution for this that actually works, or is this the Holy Grail of all IT? Please hold off on any Google haters, that's a different discussion for a different forum.